3-D imaging via free-hand scanning with a multiplane US transducer

ABSTRACT

An ultrasound imaging system includes a biplane ultrasound probe and a console. The biplane ultrasound probe includes a sagittal array and a transverse array. The console includes a transmit circuit, a receive circuit, and an image generator. The transmit circuit is configured to control the sagittal and transverse arrays to emit ultrasound signals while the probe is manually rotated and translated. The receive circuit is configured to receive electrical signal produced by the sagittal and transverse arrays in response to the sagittal and transverse arrays receiving echoes produced in response to the corresponding ultrasound signals interreacting with structure. The image generator is configured to construct a three-dimensional image with the electrical signals from the sagittal or transverse array using the electrical signals from both the sagittal and transverse arrays to track the motion of the probe and align scanplanes.

TECHNICAL FIELD

The following generally relates to ultrasound and more particularly tothree-dimensional (3-D) ultrasound imaging via free-hand scanning with amultiplane ultrasound (US) transducer.

BACKGROUND

An ultrasound imaging system has included an ultrasound probe with atransducer array and a console. The ultrasound probe houses thetransducer array, and the console includes a display monitor and a userinterface. The transducer array transmits an ultrasound signal andreceives echoes produced in response to the signal interacting withstructure. The echoes are converted to electrical signals by thetransducer array and are conveyed to the console. The console processesthe electrical signals, producing an image.

For three-dimensional (3-D) imaging, various approaches have beenemployed. For example, one approach is to use a probe with a mover thatrotates the probe or transducer array where data is acquired during themovement to acquire volumetric data. Unfortunately, external moversattached to the outside of the probe are in the way of external needleguides e.g., for biopsy needles, and internal movers occupy space insidea probe preventing the passing of a biopsy needle therethrough andexternal guides shadow the field of view.

Another approach is to use a two-dimensional (2-D) transducer array. A2-D array, relative to a one-dimensional (1-D) array, includes moretransducer elements and thus more interconnects and channels.Unfortunately, this adds cost, weight, and complexity, and requires alarger cable between the probe and the console with more wires. Anotherapproach is to use a transducer with two one-dimensional arrays in afixed geometrical structure and visually presenting the images from thedifferent arrays where the clinician mentally reconstructs a 3-D volumeform the 2-D planes. Unfortunately, the manner in which the planesintersect is not intuitive.

SUMMARY

Aspects of the application address the above matters, and others.

In one aspect, an ultrasound imaging system includes a biplaneultrasound probe and a console. The biplane ultrasound probe includes asagittal array and a transverse array. The console includes a transmitcircuit, a receive circuit, and an image generator. The transmit circuitis configured to control the sagittal and transverse arrays to emitultrasound signals while the probe is manually rotated and translated.The receive circuit is configured to receive electrical signals producedby the sagittal and transverse arrays in response to the sagittal andtransverse arrays receiving echoes produced in response to thecorresponding ultrasound signals interreacting with structure. The imagegenerator is configured to construct a three-dimensional image with theelectrical signals from the sagittal or transverse array using theelectrical signals from both the sagittal and transverse arrays to trackthe motion of the probe and align scanplanes.

In another aspect, a method includes employing a biplane transducerprobe of a first imaging modality to acquire data in both sagittal andtransverse planes while the probe is manually translated. The methodfurther includes tracking rotational motion of the probe with data forthe transverse planes. The method further includes trackingtranslational motion of the probe with data for the sagittal planes. Themethod further includes generating volume data with the data for thesagittal or transverse planes using the tracked rotational andtranslational motions to align the data in the volume.

In another aspect, a console of an ultrasound imaging system includes atransmit circuit, a receive circuit, and an image generator. Thetransmit circuit is configured to control sagittal and transverse arraysof a biplane probe to emit ultrasound signals while the probe ismanually rotated and translated. The receive circuit is configured toreceive electrical signal produced by the sagittal and transverse arraysin response to the sagittal and transverse arrays receiving echoesproduced in response to the corresponding ultrasound signalsinterreacting with structure. The image generator is configured toconstruct a three-dimensional image with the electrical signals from thesagittal or transverse array using the electrical signals from both thesagittal and transverse arrays to track the motion of the probe andalign scanplanes.

Those skilled in the art will recognize still other aspects of thepresent application upon reading and understanding the attacheddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

The application is illustrated by way of example and not limitation inthe figures of the accompanying drawings, in which like referencesindicate similar elements and in which:

FIG. 1 schematically illustrates an example ultrasound imaging systemwith a probe including a biplane transducer array;

FIG. 2 schematically illustrates a perspective view of an example of theprobe;

FIG. 3 schematically illustrates a side view of the example probe;

FIG. 4 schematically illustrates the example probe rotating andtranslating and field of views only of the sagittal array;

FIG. 5 illustrates a sagittal and a transverse field of view at oneangle of the rotation;

FIG. 6 illustrates a sagittal image;

FIG. 7 illustrates a transverse image;

FIGS. 8 and 9 provide a non-limiting example for determining a datapoint for a 3-D image using a synthetic aperture algorithm; and

FIG. 10 illustrates an example method in accordance with anembodiment(s) herein.

DETAILED DESCRIPTION

FIG. 1 schematically illustrates an imaging system 102, such asultrasound imaging system, including an ultrasound probe 104 and aconsole 106.

The probe 104 includes at least two transducer arrays 108, each arrayincluding a plurality of transducer elements 110. The at least twotransducer arrays 108 are spatially arranged in the probe 104 transverseto each other. For example, in one embodiment the probe 104 is a biplaneprobe with two transducer arrays, a sagittal array and a transverse(axial) array, which are spatially arranged transverse to each otherwhere their fields of view cross. Each of the transducer arrays 108 canbe a 1-D, 2-D etc. array. Examples of 1-D arrays include 16, 64, 128,196, 256, etc. element arrays. 2-D arrays can be square, rectangular,circular, etc.

The transducer arrays 108 are configured to generate pressure waves inresponse to excitation signals. The transducer arrays 108 are furtherconfigured to receive echo signals, which are produced in response to aninteraction of the pressure waves with structure such as anatomicaltissue, organs, cells, etc., and produce electrical (RF) signalsindicative of the received echo signals. The electrical signals aretransferred to the console 106 via a communication path 112, which caninclude a hardware channel (e.g., a cable) and/or a wireless channel.

For some procedures, the probe 104 is manually rotated by hand (freehand) during scanning and acquires data at a plurality of angularlyoffset field of views. The probe 104 may also be translated (e.g.,pushed and/or pulled), e.g., intentionally e.g., to scan a largerobject. The probe 104 may also be unintentionally translated throughunintentional hand movement. An example of such a procedure is prostateimaging. For this, the probe 104 is an endocavitary probe and ultrasoundexamination is performed transrectally. The probe is first positionedclose to the prostate, and then data is acquired with the at least onearray 108 while the user rotates (and/or translates) the probe 104 overan arc.

The console 106 includes a transmit circuit 114 and a receive circuit116. The transmit circuit 114 transmits a control signal(s), via thecommunication path 112 and to the probe 104, that excites one or more ofthe transducer element(s) 110 of the transducer arrays 108, which causesthe transducer element(s) 110 to transmit the pressure wave. The receivecircuit 116 receives, via the communication path 112 and from the probe104, the electrical signals produced by the element(s) 110 of thetransducer array 108.

The console 106 further includes a beamformer 118 configured to processthe received electrical signals. In one instance, this includesbeamforming individual sagittal and transverse scanplanes,plane-by-plane, from the electrical signals. In another instance, thebeamformer 118 employs a synthetic aperture algorithm to compute datapoints for a volume from the electrical signals. Other processing maylower speckle, improve specular reflector delineation, and/or includesFIR filtering, IIR filtering, etc. The electrical signals can first beamplified and/or otherwise pre-processed and/or conditioned.

The console 106 further includes an image generator 120. The imagegenerator 120 is configured to process individual sagittal andtransverse scanplanes and/or the data points for the volume andgenerates a 3-D image. As described in greater detail below, in oneinstance the image generator 120 uses the data from both the sagittaland transverse scanplanes as alignment/tracking planes to estimatetranslational and rotation movement of the probe 104 which is used totranslationally and/or rotationally align the sagittal scanplanes and/orthe data points to generates the 3-D image. In one instance, this canmitigate unintentional free-hand translational movement of the probe 104during scanning and/or provides a measurement accurate 3-Dreconstruction.

The console 106 further includes a display 122 configured to displayindividual image scanplanes and/or the 3-D image. The console 106further includes a data analyzer 124. The data analyzer 124 isconfigured to analyze the scanplanes. This includes estimating the abovenoted translational and rotation movement from the sagittal andtransverse scanplanes. This also includes determining whether the probe104 is being rotated too fast or too slow from the transversescanplanes. The results of the analysis can be visually presented viathe display 122 through text, numbers, color, graphical indicia, acombination thereof, and/or otherwise, e.g., through an audible and/orhaptic signal.

The console 106 further includes a user interface (UI) 126, whichincludes at least one or more input devices (e.g., a button, atouchscreen, etc.), which allows for interaction with the system 102.Such interaction may include segmenting, rotating, panning, zooming,and/or otherwise manipulating displayed data. The console 106 furtherincludes a memory device (“memory”) 128 that can be used to store theelectrical signals, the sagittal and transverse scanplanes, the 3-Dimage, etc. The console 106 further includes a controller 130 configuredto control one or more components of the console 106.

FIGS. 2 and 3 schematically illustrate a non-limiting embodiment of theprobe 104 configure as a biplane transducer. FIG. 2 shows a perspectiveview of the probe 104, and FIG. 3 shows a side view of the probe 104.

In FIGS. 2 and 3, the probe 104 includes a handle 202, a shaft 204, ahead 206, a sagittal array 208 (of the arrays 108) behind a firstacoustic window 210 and configured to provide a sagittal field of view(FOV) 212, and a transverse array 214 (of the arrays 108) behind asecond acoustic window 216 and configured to provide a transverse FOV218. Another example of a suitable biplane probe 104 is described inU.S. Pat. No. 9,259,208 B1, filed Oct. 20, 2009, and entitled“Ultrasound Probe,” which is incorporated herein by reference in itsentirety. Other suitable probes include but are not limited to theI12C5b, E14C4t, E10C4 and/or E14CL4b probes, products of B-K MedicalApS, Herlev, DK. Although the illustrated arrays 208 and 214 areperpendicular to each other, it is to be understood that the arrays 208and 214 do not have to be perpendicular to each other.

FIGS. 4-7 illustrate example data acquisition using free-hand motion andgeneration of a 3-D image from the acquired data.

FIG. 4 shows acquisition where an operator rotates the probe 104 throughan arc 402. Data for a number of sagittal FOVs 212 ₁, . . . , 212 _(N),where N is a positive integer, is acquired while the probe 104 rotates.The corresponding transverse FOVs 218 are not shown in FIG. 4, e.g., soas not to visually obscure the sagittal FOVs 212 ₁, . . . , 212 _(N).However, it is clear from the description herein that the transverseFOVs 218 rotate therewith. FIG. 4 also shows intentional and/orunintentional translational motion 404.

FIG. 5 shows a sagittal FOV 212 _(i) and a transverse FOV 218 _(i),where i is an index, at a particular angle along the arc 402 inconnection with an object 502 (e.g., an anatomical organ such as aprostate). FIG. 6 shows a sagittal image 602 _(i) for the sagittal FOV212 _(i) and includes a sagittal slice 604 _(i) of the object 502, andFIG. 7 shows a transverse image 702 _(i) for the transverse 218 _(i) andincludes a transverse slice 704 _(i) of the object 502. In FIGS. 4-7,the sagittal FOVs 212 lies in a z-y plane and the transverse FOVs 218lies in an x-y plane of a Cartesian coordinate system.

For data acquisition, the user first rotates the probe 104 in onedirection until the image for the transverse FOV does not include any ofthe objects 502. This marks the beginning of the arc 402. The user thenuser rotates the probe 104 in the opposite direction and through the arc402, acquiring data with both the sagittal and the transverse arrays 208and 214, and finishing when an image for the transverse FOV that doesnot include any of the object 502. This marks the ending of the arc 402.This assumes no intentional translational movement.

To estimate the translational and rotation movement of the probe, thedata analyzer 124 estimates a degree of rotation and translation fromone frame to a next frame (i.e. frame-to-frame). In one instance, theparameters estimated for this are those of an affine transform, which,generally, is a function between affine spaces which preserves points,straight lines and/or planes through translation, rotation, and/orstretching. An example of an affine transform matrix describing a changefrom frame k to frame k+1 is the following:

$\begin{bmatrix}{\cos(t)} & {\sin(t)} & {bx} \\{- {\sin(t)}} & {{cost}(t)} & {by} \\0 & 0 & 1\end{bmatrix}.$To place samples from the frame k+1 relative to samples from the frame kin 3-D space, all samples from the frame k+1 are translated by an amount(x,y)=(bx, by) in the x-y plane, where the x-y plane is the plane of theprimary tracking image, and rotated by “t” radians in the x-y plane.Correspondingly, the motion of the probe in the y-z-plane, voluntary ornot, may be estimated from the images of the imaging array, i.e. thearray that is used for building the 3-D volume. In one instance, onlythe displacement, bz, in the z-direction is estimated. In anotherinstance, another affine transform matrix, constrained by a givendisplacement in the y-direction, may be estimated:

$\begin{bmatrix}0 & 0 & 1 \\{- {\sin(v)}} & {{cost}(v)} & {by} \\{\cos(v)} & {\sin(v)} & {bz}\end{bmatrix}.$To place samples from the corrected frame k+1 relative to samples fromthe frame k in 3-D space, all samples from the corrected frame k+1 aretranslated by an amount (y,z)=(0, bz) in the y-z plane and rotated by“v” radians in the y-z plane.

In another instance of data acquisition, the user may choose to push orpull-back of the transducer as the primary motion of the transducer. Inthat case, the images of the transverse array are used for building thevolume, and the sagittal array is the primary tracking array. Also inthis instance, a 3-D volume may be built by estimating the parameters bytwo affine transforms.

In another instance of data acquisition, the organ may be too large tobe covered by a single sweep causing the user to perform two or moreoverlapping sweeps of the organ. In this case, a number of partlyoverlapping volumes are created. For data processing and visualization,the overlapping volumes are combined to a single volume. In oneinstance, the partly overlapping volumes are resampled to a common,regular 3-D sampling grid. This can be done in three parts. In the firstpart, each of the partial 3-D volumes is resampled to a regular samplinggrid using interpolation of samples from the nearest frames. Each ofthese partial volumes are defined by the location and orientation of thefirst frame in the partial volume. In the second part, one of theregular 3-D sampling grids is selected as the common reference.Furthermore, the displacement and rotation of each of the other regularsampling grids to the common reference is estimated. In the third part,the data from the original frames are resampled to the common, regularsampling grid using interpolation.

The number of frames to make the 3-D image depends on the 3-D algorithm.For synthetic aperture beamforming, a maximum rotational speeddetermines the number of frames. If only the volume of the object ofinterest is being computed, then fewer frames are required. With otheralgorithms, the rotational speed is determined by the user. Generally,for a five to twelve second (5-12 s) scan at approximately twenty framesper second (25 fps), the images will have about three hundred andseventy-two (372) lines.

The data analyzer 124 determines a rotational speed and compares it witha predetermined maximum rotational speed range. For synthetic apertureimaging, the maximum rotational speed is set by half the beam-width at anarrowest point of the beam from the imaging plane, measured in thetransverse direction. The data analyzer 124, as briefly discussed above,can visually present the results, which may include the rotational speedis too slow or too fast, or within the predetermined range. As discussedherein, this can be through text, numbers, color, graphical indicia,etc.

FIGS. 8 and 9 provide a non-limiting example for determining a datapoint for a 3-D image using a synthetic aperture algorithm.

FIG. 8 shows a line 802 ₁ for a plane 804 ₁ and a line 802 ₂ for a plane804 ₂. The line 802 ₂ is angularly displaced from the line 802 ₁ by anangle α, with respect to an axis of rotation 806, and hence the lines802 ₁ and 804 ₁ are at different angles of rotation of the probe 104.The lines 802 ₁ and 804 ₁ have a same position relative to the array214, which is rotated. The beams have a fixed focus in the transversedirection, which is the direction of rotation, and the focus isdetermined by a focusing lens. The electrical signals from the two lines802 ₁ and 804 ₁ are beamformed, which creates new lines, which havedynamic focusing in the transverse plane.

In these figures, {right arrow over (o)}₁ represents a center of anelement 110 in a plane n=1 (FIG. 8), and {right arrow over (o)}_(n)represents a center of the element 110 in a plane n (FIG. 9). The line802 ₁ is formed in the plane n=1 and is perpendicular to the element110, and the line 802 ₂ is formed in the plane n=2, which is angularlydisplaced from the plane n=1 by the angle α, and is perpendicular to theelement 110. {right arrow over (v)}₁ and {right arrow over (v)}₂represent virtual sources (fixed focus in elevation) for the planes n=1and n=2. {right arrow over (p)} represents a point in the scannedvolume, where the beam is focused in the elevation direction.

A signal at any point can be determined as shown in EQUATION 1:

$\begin{matrix}{{{s\left( \overset{\rightarrow}{p} \right)} = {\sum\limits_{n \in {N{(\overset{\rightarrow}{p})}}}\;{y_{n}\left( \frac{2\left( {{{{\overset{\rightarrow}{v}}_{n} - {\overset{\rightarrow}{o}}_{n}}} + {{\overset{\rightarrow}{p} - {\overset{\rightarrow}{v}}_{n}}}} \right)}{c} \right)}}},} & {{EQUATION}\mspace{14mu} 1}\end{matrix}$where s({right arrow over (p)}) represents the signal, N({right arrowover (p)}) represents a set of planes that span the point {right arrowover (p)}, y_(n) represents beamformed RF lines, {right arrow over(v)}_(n) represents a virtual source in a plane n, {right arrow over(o)}_(n) represents a center of an element in the plane n, and crepresents the speed of sound. In other words, the signal s({right arrowover (p)}) at a point {right arrow over (p)} is a summation of allsamples from the beamformed RF lines y_(n)(t) for those planes n whoseextent in elevation direction spans the point {right arrow over (p)}.The time instances t are calculated as the propagation time from anorigin of the beam {right arrow over (o)}_(n) through the virtual source{right arrow over (v)}_(n) to the point of interest {right arrow over(p)} and back to the element 110.

FIG. 10 illustrates a method in accordance with an embodiment describedherein.

It is to be appreciated that the order of the following acts is providedfor explanatory purposes and is not limiting. As such, one or more ofthe following acts may occur in a different order. Furthermore, one ormore of the following acts may be omitted and/or one or more additionalacts may be added.

At 1002, ultrasound signals are transmitted from two arrays of a biplanetransducer array during a scan in which the probe is manually rotatedduring data acquisition.

At 1004, a transverse scanplane from the transverse array is employed totrack rotational motion of the probe and unintentional translationalmotion of the probe, as described herein and/or otherwise.

At 1006, a sagittal scanplane from the sagittal array employed to tracktranslational motion of the probe and unintentional rotational motion ofthe probe, as described herein and/or otherwise.

At 1008, a 3-D image is generated with the sagittal scanplanes usingboth the tracked rotational and translational motion, as describedherein and/or otherwise.

The approach described herein allows for an accurate 3-D ultrasoundvolume to be constructed using only free-hand scanning. Below describesseveral non-limiting applications of the approach described.

In one instance, the biplane transducer is used where one array is usedfor alignment/registration and the other array for the data acquisitionof the 3-D image. The alignment array performs in-plane motion until theentire organ of interest is captured by the other array. The data fromneighboring frames from the alignment array are co-registered, providinga change of orientation of the imaging array from frame to frame in 3-Dspace. For example, the data from neighboring frames are fit togetherusing the estimates of translation and rotation. The 3D image isconstructed by scanconverting the data from the array that does notperform the in-plane motion. Panoramic imaging allows on-the-flyaccurate measurements of the translation and rotation and a measure offidelity of the registration to ensure that out of plane motion isdetected and flagged to the user, improving the acquisition of dataand/or providing a fidelity measure for the entire 3-D reconstruction.

In another instance, data from both transducer arrays are used forregistration. This is useful for capturing data of an object that is toolarge to be visualized in full during a single sweep, e.g. a prostateenlarged due to benign prostatic hyperplasia (BPH). The transducermotion in this case may be a combination of slowly pulling thetransducer while rotating it back and forth. In this case, panoramicimaging is applied in both imaging planes to robustly reveal the motionof the arrays.

In another instance, the acquired volume is used for accurateregistration to volumetric data from other modalities such as magneticresonance imaging (MRI), e.g., for ultrasound guided biopsies. Thevolume may also be overlaid with pseudo-data such as the expected pathfor a biopsy needle.

In another instance, the acquired volume is used to automaticallysegment an accurate prostate volume, which is a challenge in ultrasound,not only because the measurements today are based on two still imagesand an assumption that the prostate is an ellipsoid but also becausethese images often fail to visualize the entire prostate for patientswith BPH making today's measurements very inaccurate for the mostinteresting group of patients.

In another instance, the approach described herein is used fordisplaying in real-time and/or during cine play the relation of thecurrent frame to a 3-D model, including the scanning object so that theorientation of the current ultrasound image to the scanning object maybe immediately understood by a user or an external reviewer of the exam.The 3D-model may be sliced in standard anatomical views providing lowerfidelity images but ones that may be readily compared with standard viewMRI data or data from an atlas. The information can be stored along withthe image data, so that a rendition of the 3D-model can changecorresponding to the way the users select a particular frame in the cinebuffer.

In another instance, the approach described herein is implemented withultrasound probe E14C4t, E10C4 and/or E14CL4b for automatic prostatevolume measurement. This includes visual cues to the operator, trackingof the motion, segmentation, and automatic volume measurement.

In another instance, the approach described herein is used to create 3-Dvolumes of not only B-mode data and flow data, but also 3D measurementsof stiffness using free hand elastography or shear-wave/acousticradiation force imaging, using the approach described herein to create3D maps of stiffness.

For example, the approach described herein can be used with shear waveelasticity imaging (SWEI), which uses acoustic radiation force offocused ultrasound to create shear waves in soft tissue to map tissueelasticity. The shear wave speed is determined by the shear modulus oftissue, which is highly sensitive to physiological and pathologicalstructural changes of tissue. The variation of the shear wave speedincreases in many tissues in the presence of disease, e.g. the canceroustissues can be significantly stiffer than normal tissue. Exampleworkflow includes: scan plane with SWEI, prompt the user to move thetransducer, track the motion, and acquire a new plane.

In another example, the approach described herein can be used withacoustic radiation force impulse (ARFI) imaging, which uses acousticradiation force to generate images of the mechanical properties of softtissue. With increasing acoustic frequencies, the tissue does notrespond fast enough to the transitions between positive and negativepressures, and energy is deposited into the tissue, which in a momentumtransfer that generates a force that causes displacement of the tissue.This displacement is detected and used to derive additional information.Example workflow includes: scan plane with SWEI, prompt the user to movethe transducer, track the motion, and acquire a new plane.

In another instance, the approach described herein can be used forgeneral 3D volume imaging for the purpose of reexamination, follow-upand/or monitoring, and/or fusion, which can replace current systems thatuse electromagnetic or optical tracking of the transducer position. Thiscan be achieved through active tracking of motion in one or more planes.

In another instance, the approach described herein can be used fortargeted biopsies. Example workflow includes: acquire 3-D volume withSWEI and/or Color, move the transducer freely and track the positionusing motion estimation from the two planes, register a currentreal-time image with the 3-D volume, and, when a suitable position isreached, perform the biopsy.

The application has been described with reference to variousembodiments. Modifications and alterations will occur to others uponreading the application. It is intended that the invention be construedas including all such modifications and alterations, including insofaras they come within the scope of the appended claims and the equivalentsthereof.

What is claimed is:
 1. An ultrasound imaging system, comprising: abiplane ultrasound probe, including: a sagittal array; and a transversearray; and a console, including: a transmit circuit configured tocontrol the sagittal and transverse arrays to emit ultrasound signals toa structure while the biplane ultrasound probe is at least one ofmanually rotated and manually translated; a receive circuit configuredto receive electrical signal produced by the sagittal and transversearrays in response to the sagittal and transverse arrays receivingechoes produced in response to the corresponding ultrasound signalsinterreacting with the structure; and wherein the console is configuredto construct a three-dimensional image with the electrical signals fromone of the sagittal array or the transverse array and a transformationmatrix $\begin{bmatrix}{\cos(t)} & {\sin(t)} & {bx} \\{- {\sin(t)}} & {{cost}(t)} & {by} \\0 & 0 & 1\end{bmatrix},$ where x and y are coordinates in an x-y plane, trepresents a rotation in the x-y plane, and b represents a translationin the x-y plane.
 2. The imaging system of claim 1, wherein the consoleis further configured to determine a manual translational motion of thebiplane ultrasound probe from the electrical signals from the sagittalarray, wherein the console constructs the three-dimensional image withthe determined manual translational motion.
 3. The imaging system ofclaim 1, wherein the console is further configured to determine a manualtranslation motion of the biplane ultrasound probe from the electricalsignals from the sagittal array for the transformation matrix and amanual rotational motion of the biplane ultrasound probe from theelectrical signals from the transverse array for the transformationmatrix.
 4. The imaging system of claim 1, further comprising: abeamformer configured to beamform the electrical signals using asynthetic aperture algorithm to generate data for the three-dimensionalimage, wherein the console constructs the three-dimensional image withthe generated data.
 5. The imaging system of claim 1, wherein theconsole is further configured to determine a manual rotational motion ofthe biplane ultrasound probe from the electrical signals from thetransverse array, wherein the console constructs the three-dimensionalimage with the determined manual rotational motion.
 6. The imagingsystem of claim 5, further comprising: a beamformer configured tobeamform individual sagittal and transverse scanplanes from theelectrical signals from both the sagittal and transverse arrays.
 7. Theimaging system of claim 6, wherein the console is further configured todetermine a manual translational motion of the biplane ultrasound probe,wherein the console constructs the three-dimensional image by spatiallyaligning the sagittal scanplanes with the manual translation androtational motion.
 8. The imaging system of claim 1, wherein thetransformation matrix estimates a degree of rotation and translationfrom frame-to-frame.
 9. The imaging system of claim 8, wherein thetransformation matrix includes an affine transform that translates androtates samples from a first frame to align the first frame with a nextframe.
 10. The imaging system of claim 1, wherein the console is furtherconfigured to determine a rotational speed of the biplane ultrasoundprobe, compare the determined rotational speed with a predeterminedrotational speed range, and display a result of the comparison.
 11. Theimaging system of claim 10, wherein the result indicates the rotationalspeed is faster than the predetermined rotational speed range.
 12. Theimaging system of claim 10, wherein the result indicates the rotationalspeed is slower than the predetermined rotational speed range.
 13. Theimaging system of claim 10, wherein the result indicates the rotationalspeed is within the predetermined rotational speed range.
 14. Theimaging system of claim 10, wherein the predetermined rotational speedrange is set by half a beam-width at a narrowest point of beam from animaging plane, measured in a transverse direction.
 15. A console of anultrasound imaging system, comprising: a transmit circuit configured tocontrol a sagittal array and a transverse array of a biplane probe toemit ultrasound signals to a structure while the biplane probe ismanually rotated and translated; a receive circuit configured to receiveelectrical signal produced by the sagittal and transverse arrays inresponse to the sagittal and transverse arrays receiving echoes producedin response to the corresponding ultrasound signals interreacting withthe structure; and wherein the console is configured to construct athree-dimensional image with a transformation matrix $\begin{bmatrix}0 & 0 & 1 \\{- {\sin(v)}} & {{cost}(v)} & {by} \\{\cos(v)} & {\sin(v)} & {bz}\end{bmatrix},$ where y and z are coordinates in y-z plane, v representsa rotation in the y-z plane and b represents a translation in the y-zplane, and the electrical signals from the sagittal or transverse array.16. The console of claim 15, wherein the three-dimensional image isconstructed by scan converting data from one of the sagittal array orthe transverse array.
 17. The console of claim 15, wherein data fromboth the sagittal array and the transverse array is used forregistration.
 18. The console of claim 15, wherein data from neighboringframes from one of the sagittal array or the transverse array areco-registered, providing a change of orientation of the other of the oneof the sagittal array or the transverse array from frame to frame in 3-Dspace.
 19. The console of claim 18, wherein the data from theneighboring frames are fit together using an estimation of degree oftranslation and rotation.
 20. The console of claim 15, wherein a numberof partly overlapping volumes are created and overlapping volumes arecombined into a single volume.
 21. The console of claim 20, wherein eachof the partly overlapping volumes is resampled to a regular samplinggrid using interpolation of samples from nearest frames to createplurality of regular sampling grids, one of the regular sampling gridsis selected as a common reference, and data from original frames areresampled to a common, regular 3-D sampling grid using interpolation.